utility to add lat lon columns to data.table by reference, joining on bgid

get expanded version of data.table, such as copy(blockgroupstats), with new lat,lon columns

Usage

latlon_join_on_bgid(x)

Arguments

x

data.table with column called bgid (as used in bgid2fips or blockgroupstats)

Value

x with 2 new columns but side effect is it updates x in calling envt

Examples

# quick map of blockgroups in 1 state, shown as blockgroup centroids
myst <- "NY"
dat <- bgpts[fips2state_abbrev(substr(bgfips,1,2)) == myst, ]
mapfast(dat, radius = 0.1)


# same but popups have all the indicators from EJScreen
myst <- "NY"
dat <- copy(blockgroupstats[ST == myst, ])
#> Error in copy(blockgroupstats[ST == myst, ]): could not find function "copy"
# add latlon cols by reference:
latlon_join_on_bgid(dat)
#> Error in latlon_join_on_bgid(dat): could not find function "latlon_join_on_bgid"
# specify useful labels for the map popups
mapfast(dat, radius = 0.1,
        labels = fixcolnames(names(dat), 'r', 'shortlabel'))


## or add the useful labels to the table 1st
names(dat) <- fixcolnames(names(dat), "r", "shortlabel")
mapfast(dat, radius = 0.1)
#> Replaced column names that were inferred to be and therefore renamed as the lat and/or lon columns!